Extended matching range tuner

Abstract

In a T network tuner, a variable shunt capacitor is provided between the signal input and ground that is ganged to the variable input matching capacitor. The operation is mechanically arranged such that, as one decreases the capacitance of the variable input matching capacitor, one increases the capacitance of the shunt capacitor to assist in high frequency matching, both to increase the maximum matchable load resistance and to decrease the minimum matchable load resistance. The variable shunt capacitor therefore assists at the high frequency ranges to bring the antenna impedances down to the transmitter output impedance, thus to establish an extended matching range tuner capable working between 160 and 10 meters.

Description

FIELD OF THE INVENTION[0001]This invention relates to antenna tuning and more particularly to the use of a variable shunt capacitor coupled to the input matching capacitor in a T network such that when the variable input matching capacitor is tuned to reduce its capacitance, the capacitance of the shunt capacitor is increased.BACKGROUND OF THE INVENTION[0002]As is well known, tuners between a transmitter and an antenna are used to match the antenna impedance to the impedance at the output of a transmitter. In amateur radio service, for instance, one is seeking to match antennas to transmitters in various bands, for instance, from 160 meters through 10 meters. When using a T network, while a variable input matching capacitor can be utilized for matching an antenna to the 50-ohm output of a transmitter at the low frequency bands, when trying to use the same circuit to tune 10-meter antennas, even when the variable input matching capacitor is completely open, there is nonetheless a min...

AI Technical Summary

Benefits of technology

This configuration enables exceptional matching performance across the entire frequency range, minimizing power loss and preventing component damage by automatically adjusting capacitance to suit varying impedance loads, thus extending the matching range and ensuring reliable operation.

Problems solved by technology

On the other hand, at 160 meters, when the input matching capacitor is almost fully engaged, the shunt capacitor is almost fully disengaged so that it is not effectively in the circuit.

On the other hand, at the higher frequencies when the load impedance is lower, unless one can remove the shunt capacitance the maximum effective input matching capacitance will be limited which limits the lowest load impedance that can be matched.

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